'C:\wmic' is not recognized as an internal or external command, operable program or batch file

You have two problems, both of which we explored in the comments above:

1. The actual WMIC binary is located at C:\Windows\System32\wbem\WMIC.exe, not C:\wmic. That path needs to be used in your PHP command.

2. You are trying to use Unix-style shell concepts (redirecting STDERR to STDOUT, chaining commands with ;, and using echo and $?) on a Windows system.

   Simply running the command without all that stuff should work:

   echo shell_exec("C:\\Windows\\System32\\wbem\\WMIC.exe cpu get loadpercentage");
   

set path Windows+Pausebreak > Advanced System Settings > Environment Variable > systme varible > path > Edit: C:\Windows\System32\wbem

or

Go C:\Windows\System32\wbem > wbemtest and connect then exit.